Existing downlink only multicast networks, such as digital video broadcasting (DVB), media forward link only (MediaFLO), and the like, have significant limitations. Network coverage is usually regional and therefore a wireless transmit receive unit (WTRU), or a mobile node, loses access to the multicast service when the WTRU moves beyond a coverage area. While a WTRU may be able to re-subscribe and receive the service over a bi-directional communication network, all of the session continuity is lost.
In existing bi-directional mobile communication networks (e.g., third generation partnership program (3GPP), multimedia broadcast multicast services (MBMS), and the like), mobility is only addressed within each respective standard. Inter-technology mobility also does not support the multicast services.
In existing hybrid networks such as overlaid downlink only and bi-directional networks, mobility may be supported at the application level with the open mobile alliance digital mobile broadcast enabler (OMA BCAST). These types of hybrid networks typically utilize a break-before-make service, which often results in long service interruptions.
FIG. 1 illustrates the architecture of a proxy mobile internet protocol (IP)v6 (PMIPv6) domain. The PMIP has been introduced for network-based mobility management. The core functional entities in the network-based localized mobility management (NETLMM) infrastructure are a local mobility anchor (LMA) and a mobile access gateway (MAG) 106. There maybe multiple local mobility anchors (LMAs) 102 in a PMIPv6 domain each serving a different group of WTRUs. The LMA 102 is responsible for maintaining the reachability state of the WTRU 108 and is the topological anchor point for WTRU's 108 home network prefixes (HNP). The MAG 106 is the entity that performs the mobility management on behalf of the WTRU 108, and it resides on the access link where the WTRU 108 is anchored. The MAG 106 is responsible for detecting the movement of the WTRU 108 to and from the access link and for initiating binding registration to the WTRU's 108 LMA 102. The WTRU 108 may be an IPv4-only node, IPv6-only node, or a dual-stack node.
The WTRU's home network prefix (WTRU-HNP) 110 is a prefix assigned to the link between the WTRU 108 and the MAG 106. More than one prefix may be assigned to the link between the WTRU 108 and the MAG 106. The proxy care-of address (Proxy-CoA) 112 is the global address configured on the egress interface of the MAG 106 and is the transport endpoint of the tunnel between the LMA 102 and the MAG 106. The LMA address (LMAA) 114 is the global address that is configured on the interface of the LMA 102 and is the transport endpoint of the bi-directional tunnel established between the LMA 102 and the MAG 106. The IPv4/IPv6 network 104 refers to the network where the mobility management of a WTRU 108 is handled using PMIPv4/PMIPv6. The PMIPv4/PMIPv6 104 includes LMAs 102 and MAGs 106 between which security associates may be set up and authorization for sending proxy binding updates on behalf of the WTRUs 108 may be ensured.
These types of existing Layer 3 mobility protocols (e.g., PMIP, session initiation protocol (SIP), and the like) are designed for unicast traffic. They lack support for multicast services. Further, existing multicast protocols such as internet group management protocol (IGMP) or multicast listener discovery (MLD) need to be enhanced to reduce the latency inherent in resuming multicast services after handover.
A method and an apparatus to enable enhanced mobility for the existing and evolving multicast services, such as multicast multimedia (e.g., mobile TV, radio, presence, micro-blogging, file sharing, podcast, social networking, and the like) is desired.